I put a small tub of eco soil stuff in my viv and then put the hypoaspis mites in that, I needed to buy two lots in the end to get rid of the mites in my case.
I put them in left for three weeks then bleached the viv again before adding more in which I left for two weeks then no more mites:2thumb:
Frontline is a much quicker alternative though but I definitely wanted to the hypoaspis mites and in the end they worked fine